Process of refining hydrocarbon oil for the purpose of removing metal ions



May 8, 1945.

STORAGE TANK H. cs; SCHUTZE 2,375,694 PROCESS, OF REFINING HYDROCARBONOIL FOR THE PURPOSE OF REMOVING METAL IONS Filed Dec. 2, 1941 PatentedMay 8, 1945 PROCESS OF REFINING HYDROCARBON OIL FOR. THE PURPOSE OFREMOVING METAL IONS Henry G. Schutze, Baytown, Tex., assignor toStandard Oil' Development Company, a corporation of Delaware ApplicationDecember 2, 1941, Serial No. 421,269

9 Claims.

The present inVentiOn relates to improvements in refining of hydrocarbonoil, and more particularly it relates to improvements in the art ofremoving from refined hydrocarbon oils small quantities of metals andmetal ions which are present therein following refining operations.

An important application of my present invention relates to removingfrom the residuums resulting from the process of preparing lubricatingoil from a reduced crude as, for example, described in the co-pendingapplication of Reuben F. Pfennig, et al., which has issued "as PatentNo. 2,339,875, January 25, 1944, in which application there is describedand claimed a method of treating a reduced crude with fused causticsoda, and thereafter discharging themixture into a separation zone wherethe caustic soda and the oil stratify, thence removing the upper oillayer, and distilling from it the color stable lubricating oil. Theresiduums of the distillation operation are ordinarily employed as abunker fuel or the like. In the type of operation described in theaforesaid application, however, the residuums from the distillationoperation contain appreciable quantities of sodium compounds which, whenpresent in the oil, would cause various difi'iculties in the furnace inwhich they were burned as a fuel. Consequently, it is necessary toremove substantially all of these sodium ions and my present invention,as hereinbefore indicated, provides suitable means for removing theseions.

In treating the residuums aforementioned, or other hydrocarbon oilscontaining sodium compounds, I cause the residuums to flow through anelongated bed of an acid reacting material which may be prepared, forexample, by the methods described in U. S. Bureau of Mines Report ofInvestigations No. 3559, of March 1941, or other materials such as thosederived from the residues resulting from treating hydrocarbon oil withsulfuric acid to form a sludge, which sludge is then coked by heating,and thereafter treated at elevated temperatures with sulfuric acid, asdescribed in the co-pending application of Joseph John Savelli, whichhas issued as Patent No. 2,337,500, December 21, 1943.

For better understanding of my invention, reference is made to theaccompanying drawing which shows'diagrammatically a form and arrangementof apparatus elements in which my invention may be carried intopractical effect. The residuums resulting from the preparation of thelubricating oil by treatment of a reduced crude with fused caustic soda,hereinbefore referred to, is introduced into the system through line I,thence dischargedinto a fired coil 3, disposed in a furnace 5 in whichthe oil is heated to a temperature of 350 F. or any suitable temperaturewhich will reduce the viscosity of the oil such as to make it readilyfiowable. Alternatively or in addition, the viscosity of the residuummay be reduced by fiuxing with kerosene, gas oil, or the like byintroducing the fluxing medium into line I by means of line 2.Thereafter the oil is discharged into an elongated vertical treatingtower 10 near the top thereof. The tower l0 contains a continuous bed ofthe aforementioned carbonaceous ion exchange material C. The oil flowsthrough the bed of carbonaceous material and during its assagetherethrough substantially all of the sodium ions contained therein areremoved by the ion exchange material. The oil is fed to the treatingtower at a rate of about 4 V/V/hour, The treated oil is withdrawnthrough line I5 and delivered to storage tank 20.

During the operation which I have just nowdescribed, there comes a timewhen the carbona-' or revivified. Obviously, the onstream period isdependent upon the amount of sodium originally contained in the oil. Theoil may contain from about 0.1 to 1%, but usually it is in theneighborhood of about 0.2% of sodium measured as sodium hydroxide. Wherethe untreated oil contains about 0.2% by weight of sodium, the oil maybe maintained on the onstream operation for a period of from about 60 to120 hours, where one volume of oil per volume of ion exchange materialis fed to the tower per hour.

As previously indicated, therefore, there comes a time when the treatingagent must be revivified and this is preferably accomplished by discontinuing the flow of oil to the treating tower and. in the case of aheavy oil, first flushing the treat ing agent with a suitable substance,such as kerosene, to remove the residual oil. This flushing oil may bepumped from pipe 25 through pipe 15 upwardly through the bed of treatingmaterial and withdrawn verhead through line 22. After the flushing oilis withdrawn, the regeneration proper is carried out by pumping fromline 25 tion for a sufficient period of time to remove all of the acidfrom the treating material and then titrating back the excess sodiumhydroxide with standardized acid.

It should be stated that the particle size most practical to employ withrespect to the treating material is one within the range of from about10 to 30 mesh.

Another important adaptation of my invention involves removing theresidual copper from hydrocarbon oils, such as gasoline, kerosene, lightgas-oil, etc., by the so-called copper sweetening process. In the coppersweetening of hydrocarbon oils, the sour oil containing mercaptans andother undesirable sulfur compounds is contacted in liquid phase with aclay impregnated with cupric chloride in the presence of an oxidizinggas, such as air or oxygen. In a similar copper sweetening process, thesour oil is treated with a solution containing copper ions.

Both of these processes are subject to the objection that minor amountsof copper compounds are contained in the treated oil. These minoramounts of copper are-highly objectionable [because they accelerate gumformation and also accelerate the production of color forming bodies.Prior to my invention it has been proposed by others to remove theseminor amounts of copper compounds .by treating the sweetened oil withsodium sulfide or other salt. As indicated previously, anothermodification of my invention involves treating copper sweetenedhydrocarbon oils by passing them through an elongated bed of thecarbonaceous ion exchange materials hereinbefo-re referred to, whereuponthe copper compounds are removed from the oil.

EXAMPLE 1 In a run which I made, I treated gasoline containing 3 partsper million of copper at ordinary temperatures and pressure for a periodof 5 minutes, and the treated oil was placed in storage for inspectionalong with a blank, with the fol-' lowing results:

Table 1 Motor fuel containing 3 P. P. M. of copper ion and percolatedthrough carbonaceous ion exchange material Motor fuel containing 3 P. P.M. ofcopper 1011 Storage period,

AS'IM Designation: ID525-40T. ASTM Standards 1940 Supplement, part III,page 211.

EXAMPLE 2 A residuum resulting from the distillation of a crudepetroleum oil was treated with fused alkali as hereinbefore describedand then was fluxed with cracking coil tar (to reduce the viscosity ofthe former) in the proportion of 2 parts of tar to 1 part of residuum.The fluxed residuum was tested and found to have the followingcharacteristics:

Table 2 Gr. API 14.5 Open cup fiash F 355 Vis. at 210 F., SSU 214Alkalinity expressed as wt. per cent NaOH 0.20

The fiuxed oil was then percolated through a filter containing acarbonaceous ion exchange material sold under the trade name of Zeo-KarbH. The filter was approximately 1 inch in diameter and about 24 incheslong and was fitted at its lower end with a rate control valve. A vacuumfilter flask connected to the bottom of the filter served as a receiverfor the oil. The fluxed oil was introduced into the top of the filterand percolated therethrough at a temperature of 350 F, with applicationof vacuum to assist in the operation. The oil collected in the filterflask was cooled and tested. The following results indicate removal ofsodium ion from the fluxed residuum by the above-described treatment:

Table 3 EXAMPLE 3 The carbonaceous ion exchange material remaining aftertreatment of the oil as described in Example 2 was regenerated bywashing with naphtha to remove heavy oil remaining in the ion exchangebed and, after drying, agitating mechanically with an excess of sulfuricacid of 50% by weight concentration for 3 to 4 hours at roomtemperature. The mixture of acid and ion exchange material was allowedto stand for about 16 hours; the acid was separated, and the ionexchange material was then washed free from acid with water. Theregenerated carbonaceous ion exchange agent was dried and was employedto treat additional quantities of the fluxed oil described in Example 2.In a like manner, the ion exchange material remaining after treating thesecond quantity of oil was regenerated and employed to treat a thirdportion of oil. Similarly the ion exchange material was regeneratedafter the third treatment of oil and was employed to treat a fourthquantity of fluxed oil and thereafter was again regenerated and employedto treat additional quantities of oil. The following data illustrate theeffectiveness of the regenerated carbonaceous ion exchange material inremoving alkalinity from fluxed crude residuum:

Table 4 Alkalinity of Vol. of oil Alkalinity of charge oil, expercolatedpercolated Percolation agent pressed as per vol. of oil, expressedWeight per Zeo-Karb as weight per cent NaOH H charged cent NaOH Zeo-KarbH," 1st regen 0. 20 22.0 0. 068 Zeo-Karb H, 2nd regen 0. 2D 12. 5 0. 09Zeo-Karb H, 3rd regen 0. 20 12. 6 0. 089 Zeo-Karb H, 4th regen 0. 20 12.0 0. 086

The above data clearly show the carbonaceous ion exchange material maybe regenerated by treatment with dilute sulfuric acid and that saidregenerated material is an effective treating reagent in removingmetallic ions such as sodium ions from petroleum oils.

To recapitulate, my present invention relates to improvements in the artof refining hydrocarbon oil and, in particular, to removing metals suchas sodium, which may be present in a lubricating oil in substantialamounts as a result of the manufacture of the oil employing fusedcaustic soda, or copper, which may result in formation of an unstablegasoline, Diesel fuel, kerosene, or the like as a result of treatingsuch hydrocarbon oil by the so-called copper sweetening method. Thebasic concept of my invention involves removing these metals bycontacting the hydrocarbon oil with an acid-reacting carbonaceousmaterial produced by treating with stron sulfuric acid vegetablematerial, certain mineral materials such as lignite, or various sludgesresulting from refining hydrocarbon oils with strong sulfuric acid.

Many modifications of my invention will readily suggest themselves tothose who are familiar with this art Without departing from the spiritthereof.

The present invention having been thus described and illustrated, whatis claimed as new and useful and is desired to be secured by LettersPatent is:

1. In the refining of petroleum oil, the improvement which comprisescontacting said oil with an acid reacting carbonaceous ion exchangematerial prepared by coking an acid sludge followed by treatment of saidacid sludge with concentrated acid at high temperature whereby the metalions contained in the said oil are at least in substantial quantityremoved therefrom.

2. The process set forth in claim 1 in which the oil to be treated is aheavy residual oil and the ion to be removed is sodium.

3. The process set forth in claim 1 in which the oil to be treated is acopper sweetened oil and the metal ion to be removed is copper.

4. The process of refining hydrocarbon oils for the purpose of removingmetal ions contained therein in minor quantities, which comprisescontinuously contacting the said oil with an acid reacting carbonaceousion exchange material prepared by coking an acid sludge followed bytreatment of said acid sludge with concentrated acid at high temperaturein a treating zone for a sufficient period of time to effect the desiredimprovement, and recovering the treated oil.

5. The process set forth in claim 4 in which the acid reactingcarbonaceous ion exchange material is periodically revivified bytreatment with an acid.

6. In the production of a fuel oil of improved quality from a chargingstock containing from 0.1 to 1% of sodium, the improvement whichcomprises causing the charging oil to flow by gravity through anelongated bed of an acid reacting carbonaceous ion'exchange materialprepared by coking an acid sludge followed by treatment of said acidsludge with concentrated acid at high temperature and recovering thefuel oil from said carbonaceous material.

'7. The process set forth in claim 6 in which the charging oil isdiluted with a relatively lower boiling hydrocarbon oil in order toreduce the viscosity thereof.

8. In the process of refining motor fuels which have been sweetened bythe copper sweetening method, the improvement which comprisescontinuously flowing the sweetened oil through an elongated zone of anacid reacting carbonaceous ion exchange material and recovering theimproved gasoline.

9. In the refining of a copper sweetened oil for the removal therefromof copper ions the improvement which comprises contacting said oil withan acid reacting carbonaceous ion exchange material whereby the copperions in the said oil are at least in substantial quantity removedtherefrom.

HENRY G. SCHUTZE.

